Bad noise, then no drive ;-(

[Fiat4Fun]

Howdy,
Took the boat out for the fourth time this season, and was having a great day, Running all over the place, full throttle, cruising, slow, everything was fine.
About five hours in, as we were pulling the kids on a four man "couch" for about 20minutes, we heard a bad sound come from the engine, very mechanical, and I cut the throttle, and then turned the engine off. Checked under the "hood" and saw nothing strange, tried to restart, and heard more mechanical noises.
We then tilted the drive up to see if something was noticeable, saw nothing strange. Then restarted, engine started, sounding a bit rough, and tried to put in the gear, and nothing……… no forward , no reverse. Check to make sure the cables were ok, and the "shoe " was moving and all was fine.
So we towed it back to the dock, and that was the end of the day……
So now I need to dig deeper. A bit of history, it is a 1986 Alpha One Gen One, with a 265 HP V8. I had it serviced at the end of last year, my mechanic found metallic dust in the oil, and the lower end was bad, sent it back to Sierra and got a new one under warranty. The upper was checked out by a mercruiser dealer, and it tested fine. We have had it out for a few times this year and no issues. I think the upper went, as it should be the weakest link, but I know the shifting is done in the lower.

I am thinking it is drive issue, as the motor seems strong.

Any advice on what to check before I tear it apart? I am thinking of just yanking the drive of the back of the boat, and seeing if something is obvious…..
Any other advice is greatly appreciated.
​Bob

 

[Scott Danforth]

pull the drive, rig the garden hose to the inlet hose, start motor. if sound is gone, definately drive is bad.

 

[tpenfield]

Yup, take the drive off and see how everything feels by turning the drive shaft by hand . . . Another possibility is the coupler on the engine, so check there as well.

 

[dubs283]

pull the drive, inspect the coupler - if its okay, pull the top cap off the drive and inspect

did either shop ever pressure test the drive??

 

[Fiat4Fun]

Thanks for the input. I suspect the drive, but didn't think about the coupler.
I will pull the drive, and check it out. What should I look for on the coupler? Sounds like if that went, were talking a major repair?
How robust is the coupler?

Both the upper and lower were pressure tested, and tested as a unit. Both seem fine. The upper is original. Is it possible something can break
in the upper and cause no drive? I know the lower does the shifting, and is the newer unit, so I would hope it would be fine…….

 

[tpenfield]

Based on what you described, you may find some damage to the spline teeth on the drive shaft of the outdrive, if it is the coupler. What you will be looking for at the coupler is ground down teeth. You can probably get a good glimpse of it once the outdrive is removed.

 

[Fiat4Fun]

OK,
Going to check the prop plastic piece, drain the drive oil, and then pull the drive.
I am going to catch all the fluid in a clean container to check the drive oil.
The oil only has about 10 hours on it max.

I hope it's obvious!
Any idea of the shipping time on SEI drives?


Thanks
Bob

 

[Marc Peternell]

From the engine back, you have the coupler, U-joint, upper gears, driveshaft, lower gears, then prop. Couple you can easily test by marking it with a line where the driveshaft enters the coupler. If they don't move at the same speed and the lines separate, there is your problem. If the coupler is good, go ahead and pull the outdrive. The first thing you can look at is the U-joint. That would be pretty obvious if it is broken. turn the driveshaft yourself with it in gear, if the lower doesn't spin, then it is your gears. Pop the top off and look down into your upper gears. You will see if they are worn out... You will also see if you have gear lube on them. If no gear lube and stripped uppers, then maybe your mechanic failed to put gear lube in there?

If the noise was an awful clanging clashing grinding noise, then it could bee the upper gears.

Let us know what you find.

 

[Fiat4Fun]

Howdy folks,
Hope everyone had a great 4th of July!
Finally got to the boat, thanks for all the suggestions.

So, I pulled the prop, plastic insert was fine
Turned the motor over, and the drive shaft was spinning and changed speeds, but I noticed that the water pump was not pulling water as it was on the muffs.
Didn't run it very long!
Pulled the drive, looked inside the bellows at the coupler, all looked good, lots of grease on the splines, no metal shavings on the drive shaft.

Drained the oil of the drive, and saw metallic in the oil ( oil only has ten hours on it)
Pulled the cap off the top end, and found metal pieces in the crown gear.
So, looks like some thing bad happened in the upper end, so I am going to pull the lower and upper apart.

But I guess I looking for a new drive, and I noticed on the side of my drive on the Mercruiser sticker it said "1.50R"

When I look at SEI's website, they don't show a 1.5. Is the 1.47 fine, or should I go to 1.67?

Any other suggestions are greatly appreciated……
Enjoy your weekend, and I hope you are on the water………..